Recently, with the development of multimedia technologies, electronic devices that have multiple functions have appeared on the market. These electronic devices generally have a convergence function for complexly performing one or more functions.
The functions of the electronic devices have being diversified, and relatively appealing and portable devices are more competitive. For example, consumers prefer electronic devices which are light-weight, slim, short, and small-sized, and use a preferred textile material (for example, a metal) even though the electronic devices have the same function. Accordingly, attempts to develop an electronic device that is light-weight, slim, short, and small-sized while having the same or an excellent function as compared with other products has been repeated.
Such attempts have even been made on antennas that are used to transmit and receive electric waves. For example, many efforts have been made to develop an antenna that can contribute to efficiently securing a mounting space of an electronic device without being influenced by a surrounding material while being smoothly operated at various frequency bands.
Recent communication electronic devices may include various types of embedded antenna units arranged within the electronic devices. In particular, when metallic objects (for example, a metal case) and metallic components are located near an antenna, the metallic structure is operated as a radiation absorption body of the antenna in order to lower radiation efficiency and reduce a frequency band.
Although conventional electronic devices have a sufficient mounting space for an antenna and a sufficient separation distance for a metal, and use a dielectric material such as plastic for an external material of a product so that there is no difficulty in designing an antenna, recent electronic devices have a smaller space for mounting an antenna unit as the sizes thereof become smaller and slimmer, and the distances between surrounding metallic objects and metallic components have become closer.
Because the metallic structure significantly contributes to an appealing external appearance and the slimness of the device, as well as the improvement of a mechanical strength, several attempts to apply the metallic structure to a part of an electronic device (in particular, a case frame) have been consistently made.
However, in regards to the conventional embedded antenna units, it is difficult to satisfy requirements such as miniaturization, improvement of efficiency, and an operation in a wide band range in an extreme surrounding condition.
A conventional method for solving the problem can achieve a smooth performance of an antenna by arranging an antenna pattern such that the antenna pattern is as distant from a metallic object as possible in a narrow mounting space using an existing antenna unit by replacing a metal object at a part where an antenna is located with a dielectric injection-molded material, or by increasing the thickness of a part where an antenna is located. However, it is difficult to secure a space any more as a mounting space for an antenna becomes smaller if an antenna pattern is distant from a metallic component and a metallic object, and it is easy to secure radiation performance if the antenna is injection-molded but a discontinuity in design is present between a metal and an injection-molded part so that an external design of the electronic device may be hampered.